JP2004132378A - High pressure pump suitable particularly for common injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure pump, successfully adaptable for requirements in each case and satisfactory with severe requirements for service life while assuring high supply pressure and high operational reliability. <P>SOLUTION: The high pressure pump comprises a plurality of individual supply pumps. The supply pumps are designed as module type pump units 2 which can be arranged adjacently to each other via their housings 22. The housings 22 have fluid connection passages 24, 26, 31, 34, 41. They also have at least one line module 1 connectable to at least one side of the housings 22 of the module type pump units 2. The fluid connection passages for the housings 22 adjacent to each other extend further at one side and/or form at the other side suction discharge passages 24", 26", 34", 41" in communication with the outside. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a high-pressure pump suitable for a co-injection device for an internal combustion engine in the preceding part of claim 1.

Co-injection devices are used in internal combustion engines where the fuel is present in a fine mist in the combustion chamber of each cylinder to maximize the combustion power. For this, the fuel is compressed by a high-pressure pump and distributed via rails to the injectors of the individual cylinders. Then, the process of injecting fuel into the combustion chamber is triggered by the electric signal, and the fuel is finely distributed under high pressure from the injection nozzle of the injector to the combustion chamber of the engine at high speed.

A high-pressure pump of the first-mentioned type suitable for a co-injection system for diesel engines is disclosed in EP-A-0 881 380. In general, high-pressure pumps of this type have a plurality of piston / cylinder supply members which make it possible to achieve high supply pressures with the required operational reliability. These primary pumps must be designed in a special way to suit the specific intended use, ie they must be specially configured in each case.

高性能 High-performance diesel engines equipped with traditional injection devices are also known. Each cylinder of the device is assigned to a pump supply. Thus, high performance diesel engines having a large number of cylinders generally require multiple injection pumps. For example, in the case of a V-16 cylinder engine, two serial injection devices each having eight pump supply members before and after are arranged between two cylinder rows. Attempts to provide a co-diesel injector for this type of engine require a high-pressure pump that is specifically adapted to power, overall size and predetermined space requirements.

No. 4,184,817 discloses a multiple cylinder high pressure plunger pump in which the plunger is sealed with two separate lip seal members. The seal member on the supply space side is lubricated with diesel oil, while at the same time ensuring that no diesel oil enters between these two lip seal members and into the space on the eccentric-drive side. ing. An annular chamber connected to the diesel suction chamber via a passage is further connected upstream of the lip seal member. The lower second lip seal member, which is located on the eccentric drive side, is used to seal the plunger against lubricating oil in the eccentric drive. A labyrinth link member is provided between the two lip seal members and only a small amount while maintaining the amount of overflow of the diesel oil and the lubricating oil into the space located between the two lip seal members and connected to the surroundings through the hole. Trapped (trap small).

The object of the present invention is to ensure a high supply pressure which can be realized in a very economical manner, a high operational reliability, be able to adapt to the individual requirements without any problem and to have a strict service life. An object of the present invention is to provide a high-pressure pump that satisfies requirements.

This object is essentially achieved by a high-pressure pump having the features of claim 1.

モ ジ ュ ー ル The modular design of the pump unit and the combination with specially designed line modules enable the high-pressure pump to be realized without any problems and in a small space. Said pumps can be adapted in the most possible way to the demands that exist in each case as a function of a particular combination of modules. The use of this combination of modules and the proper design of the passages also provide optimal guidance for the low pressure supply and high pressure removal of fuel, especially diesel oil, elimination of leaks, and lubrication oil supply and oil return flow lines. You can also achieve.

モ ジ ュ ー ル Each modular pump unit, which is in each case preferred, has at least two plungers which are diametrically opposed to one another and are driven by the same eccentric, together with the associated supply space and the common housing. Preferably, the supply space and the plunger hole are formed in a high-pressure component screwed into the housing.

The line module or the plurality of line modules that may be present can be arranged with great freedom within the overall configuration of a particular high-pressure pump, for example by being able to optimize the connection points in individual cases. is there.

In one preferred embodiment, the line module forms the end of a high-pressure pump in which this type of line module is arranged between the pump modules or this type of line module consists of individual modules. In either case, it can be configured to have a bearing for the drive shaft.

According to the present invention, a plurality of plungers can be provided in a high-pressure pump having a modular configuration according to the method described in particular. The plungers are reciprocated by a common drive shaft provided with an eccentric part and are guided in each case in a plunger hole leading to the supply space, in particular through a cup tappet guided in a hole in the housing. It is driven by the eccentric against the action. In this case, firstly, an eccentric space through which the drive shaft passes, and secondly, at least one annular lubricating passage surrounding the respective plunger or cup tappet and formed in the housing is provided to the lubricating oil supply. An annular space which is connected and connected to the lubricating oil return flow is provided in a partial area of the plunger or cup tappet on the supply space side. Furthermore, an annular collecting space for overflowing lubricating oil and diesel oil is formed on the side of the plunger hole wall on the side of the supply space and is connected via a passage, in particular to a diesel oil tank.

The improvement of such a high-pressure pump firstly causes an increase in service life, and secondly, prevents diesel oil from entering the space of the eccentric drive unit filled with lubricating oil, and conversely, lubricating oil Do not mix with diesel oil. This mixture is injected shortly or later into the combustion chamber of the engine via the injection nozzle and has a negative effect on the emission of exhaust gases from the engine.

Separation of diesel and lubricating oils is obtained in a simple manner and is error free.

Another aspect which is essential in the present invention and is generally usable for this type of high pressure pump is to replace the conventionally provided rotating ring between the eccentric drive and the driven plunger or cup tappet. And a slide shoe having a two-part design. The configuration of the rotary member in the form of a two-piece slide shoe makes it particularly easy to mount and allows this type of rotary member to be mounted even when a conventional rotary ring cannot be used.

Further advantageous advantages and features which are important for the invention are described in the dependent claims and in the following description of exemplary embodiments with reference to the drawings.

FIG. 1 schematically shows a pump unit 2 (shown in cross section) of a high-pressure pump for a co-injection device of an internal combustion engine. The high-pressure pump is composed of a pump unit of this type and a line module 1, which will be described in detail later. The storage volumes 6 ′ of the common rail 6, which are supplied via a high-pressure output line 26, are each connected to the injector 5 in a known manner via a high-pressure connection line 4.

ポ ン プ The pump unit 2 shown in cross section comprises two plunger units which are respectively arranged diametrically opposite and which in each case are formed by the plungers 14. The plunger 14 is guided so as to reciprocate in a hole 37 and is assigned a cup tappet 36 guided in the housing 22. The plunger 14 having the cup tappet 36 is urged by the return spring 50 against the eccentric drive units 10 and 11. The plunger hole 37 is connected to the low pressure supply line 24 via the pressure control inlet valve 25 and to the supply space 18 connected to the high pressure output line 26 via the pressure control outlet valve 27. The low pressure supply line 24 is connected to the diesel oil tank 33 having the ventilation means 57 through the suction line 23 connected to the low pressure front supply pump 21 in particular. The flow rate adjusting member 3 is arranged in the low pressure supply line 24 for diesel oil.

The housing area of the plunger hole 37, the supply space 18, and the valves 25 and 27 is formed in the high-pressure component 7 screwed to the housing 22.

The plunger 14 or the cup tappet 36 is driven by the drive shaft 9 whose rotation center is indicated by reference numeral 63. An eccentric portion acting on the cup tappet 36 is denoted by reference numeral 10. Between the eccentric 10 and the cup tappet 36 the rotating ring 11 is arranged in a conventional manner. A sliding bearing 12 or a ball bearing is provided between the rotating ring 11 and the eccentric member 10. The eccentric center is indicated by the letter E and the maximum eccentric distance is indicated by H / 2.

In the area separating the high-pressure component 7 and the housing 22, an annular space 34 '(described in detail below) extends so as to provide a passage for the high-pressure hole such that an overflow occurs at the branch point of the high-pressure hole. The volume can completely penetrate into said space 34 '.

The centrally symmetrical design of the pump unit 2 already described is evident from FIG. 1, which also applies to the lower part of the pump unit, so it is sufficient to describe the upper part of this pump unit. The method employed for lubrication and the method employed for separating lubricating oil and diesel oil will be described in detail with reference to another drawing.

2 shows a high-pressure pump constructed in a modular manner according to the invention and having a modular pump unit 2 and, in this case, a line module 1 arranged centrally. Overall, there are eight plungers assembled to form the pump. This arrangement is particularly advantageous because it allows the construction of a narrow and tall pump similar to a traditional series injection pump. This makes it possible, for example, to accommodate the pump according to the invention in the existing structural space between the rows of cylinders of a V-type engine without any problems.

The effective lubrication in the individual pump units and the way to guide the lubricating oil and diesel oil and their leakage are described with reference to the pump unit 2 (shown at the left end of FIG. 2) as a representative of all pump units. Is done.

The annular space 45 arranged on the cup tappet 36 is connected to the lubricating oil tank 40 (shown in FIG. 3) via the forced oil line 31 extending through the entire configuration of the high-pressure pump. The lubricating oil is supplied at a required pressure by a supply pump 19. This feed pump 19 is used to feed the bearings of the drive shaft 9 (eccentric shaft) in the same way as the lubricating oil, in particular via the axial lubricating oil passage 30 and the radial bore 46. The oil overflowing from the bearing of the drive shaft 9 flows into the eccentric space 58.

The supply pump 19 can be a lubricating oil pump for the engine. In this case, the lubricating oil tank 40 simultaneously becomes an engine lubricating oil tank.

In the working area at the open end of the cup tappet 36, another annular space 41 is connected via a passage 41 parallel to the axial direction to a passage 41 '' which extends inside the line module 1 outwardly and perpendicularly thereto. 'Is provided. Instead of the passage 41, an opening may be formed in a lower region of the cup tappet 36. In this case, the oil overflowing from above the cup tappet 36 flows from the space 41 'through the internal space of the cup tappet 36 to the eccentric space 58 from the opening.

環状 An annular collecting and mixing space 35 is formed on the inner wall of the plunger hole 37 in the high-pressure component 7. The collection mixing space 35 is connected to the annular space 34 'via a passage 60. The annular space 34 ′ is connected via a passage 34 formed in the housing 22 to a passage 34 ″ that is formed perpendicularly to the line module 1 and leads to the outside. An O-ring seal seals the annular space 41 'from the annular space 34'.

The effect achieved by this improvement is firstly that the cup tappet 36 is reliably and sufficiently lubricated, and secondly, that the lubricating oil does not enter the annular space 34 ′ and thus the supply space 18. The point is to make sure.

In addition to the two passages 34 '', 41 '', passages for the low pressure supply line 24 (see FIG. 1) for the diesel oil and high pressure output line 26 '' are also formed in the line module 1. I have. The passage 24 '' assigned to the low pressure supply line is not visible in FIG. 2, but is indicated by the dotted line in FIG.

The flow of the lubricating oil guided through the passage 31 and leading to the annular space 45 enters the annular space 41 'during operation, and returns from there to the oil tank 40 via the passages 41 and 41' '. The oil tank 40 may be an oil sump of an engine provided with a high-pressure pump.

Both the lubricating oil leak and the diesel oil leak from a very small gap between the plunger 14 and the plunger hole 37 enter the annular space 35, where the leaks mix. The mixture is removed from the high pressure pump via passage 60, space 34 'and passages 34, 34' '. The mixture of the overflowed diesel oil and the overflowed lubricating oil can be returned to the diesel tank 33 shown in FIG. The proportion of the overflowed lubricating oil in the overflowed diesel oil is preferably less than 1% and can be kept very low, only 2% at certain locations. The amount of the lubricating oil that has overflowed into the diesel tank 33 is further diluted therein, and is then injected from the supply space 18 through the injection device and finally into the engine combustion chamber. Exhaust gas quality is not adversely affected by the small amount of lubricating oil contained in the injected fuel. The amount of the lubricating oil that overflows is very small because the gap between the plunger 14 and the plunger hole 37 is extremely small. Further, the viscosity of diesel oil is substantially lower than the viscosity of lubricating oil, and the pressure in the supply space 18 during the supply stroke is 1000 times higher than the lubricating oil pressure. These facts make overflowing diesel oil dominant over overflowing lubricant. Further preferred refinements for keeping the amount of lubricating oil overflowing very low are explained in more detail in connection with FIG.

Similarly to the case where the high-pressure component 7 is sealed with respect to the housing 22 by the high-pressure seal member 8, a high-pressure seal member 8 ′ is provided between a specific housing 22 and the adjacent line module 1. Yet another seal (eg, an O-ring) is used as a low pressure seal for the holes 31, 34, 41. In this manner, a leak proof coupled line device is provided by holes such as 24, 26, 31, 34, 41 provided in the housing 22. This device is connected to the corresponding lines or passages 24 ″, 26 ″, 34 ″, 41 ″ in the line module 1 so that pure lead-through channels and / or The line module 1 can be designed to have a passage leading to the outside. Furthermore, the central bearing 59 of the drive shaft 9 is arranged in the line module 1 and is dimensioned such that the drive shaft 9 together with the eccentric 10 can be pushed through the bearing for mounting. And size.

端 At one end of the high-pressure pump, an end piece 15 in which pressurized oil supply passages 30 and 31 for lubricating oil are provided is hermetically mounted on the end face 13 of the housing.

FIG. 3 shows a supply pump 21 and an associated diesel oil tank 33 having a front pipe, and a lubricated air supply as well as the supply pump 19 and the forced oil line 30 with respect to the high-pressure pump already described with reference to FIG. An oil tank 40 is shown. The forced oil supply to the bearings of the drive shaft 9 via the holes 46 is also shown in FIG.

It is particularly advantageous for the pressure maintenance valve 32 to be located in the 'overflow line 34'. The overflow line 34 ′ leads a leaky mixture of diesel oil and a small amount of lubricating oil and is connected to the annular collecting and mixing space 35. A pressure maintaining valve 32, for example loaded with a compression spring, makes it possible to produce some pressure increase upstream of the valve and thus in the annular collecting cavity 35. Due to the pressure increase in said space 35, the direction of flow of the leak is influenced so that virtually no lubricating oil enters the mixing space 35. This is an essential requirement for the high-pressure pump according to the invention.

However, in this case, a very small amount of diesel oil can flow from the annular collecting space 35 to the oil recirculating annular space 41 ′ and further to the lubricating oil tank 40 according to the pressure increase. However, since the amount of the diesel oil is very small, the lubricating oil is diluted only slightly, but not substantially diluted. In this case, the mixing of very small amounts of diesel oil with lubricating oil is not a problem, both in terms of oil quality and combustion.

Further, the mixing of the diesel oil and the lubricating oil in the annular collecting and mixing space 35 is influenced by the distance "L" of the extremely small gap between the plunger 14 and the plunger hole 37. It is particularly preferable that “L” is 2 × E = H, that is, larger than the stroke of the eccentric member 10 and the plunger 14. During the stroke of the plunger, the particles move at most a distance H in a very small gap. As the pressure in the annular space 35 increases, the mixing can be effectively prevented.

The two criteria of pressure increase and distance "L" may be employed independently of each other.

In one variation (not shown), the pressure maintenance valve 32 may be configured to adapt the pressure increase in the annular space 35 to the operating conditions of the pump and / or engine (eg, electrical) in order to obtain minimal mixing. Controlled electronically or electronically).

4 shows the location of the passages running parallel to the axial direction in FIGS. 2 and 3, in particular the holes 24 '' which are not visible in FIG. 2 but constitute a low-pressure supply line for diesel oil.

FIG. 5 shows an improvement of the modular high-pressure pump of the present invention expanded compared to the embodiment of FIG. In this case, three modular pump units 2 are combined with two line modules 1 to use a total of 12 cylinder / plunger units. In this refinement, it can be seen that the line module 1 can be formed to have both a solely continuous passage and a continuous but diverging passage. Both line modules 1 can be used simultaneously for mounting the drive shaft 9.

FIG. 6 shows fewer high pressure pumps than the embodiment of FIG. Here, only four plungers are used in total. The plunger is provided on the high-pressure component 7 in the housing 22 as described above.

The line module 1 used here is also used for mounting the shaft, but on the one hand has a passage leading to the outside, and on the other hand has a continuous passage 31 for the forced oil supply of the pump. are doing. The housing 22 is identical to that of FIGS. The line module 1 serves the function of the outer end wall of the housing and is slightly modified as not all passages are visible.

FIG. 7 shows a cross section of a pump similar to that of FIG. 1, except that the rotary ring 11 is replaced by two-piece slide shoes 47, 47 '. The two slide shoes 47, 47 'are held together by screws 48. A sliding bearing or a ball bearing can be provided between the eccentric part 10 and the two-piece slide shoes 47, 47 '. Since the eccentric space 58 is filled with lubricating oil, no adverse friction occurs between the plane 64 of the slide shoes 47, 47 'and the selectively actuated cup tappet 36 or plunger 14.

A substantial advantage of arranging the slide shoes is that the rotating ring 11 used in the above-described drawing between the line modules 1 can be mounted without any problem even if it cannot be pushed by the bearing 59. .

If appropriate, a combination of a rotating ring and a slide shoe may be used, but it is preferable that all the rotating rings are replaced by slide shoes 47, 47 '.

FIG. 3 is a schematic view of a pump unit having a common rail, and is a cross-sectional view taken along line II of FIG. 2. 1 is an axial longitudinal sectional view of a high-pressure pump having a modular configuration according to the present invention. FIG. 3 is a partial view of the high-pressure pump of the present invention having a centrally located line module (partially shown) and assigned diesel and lubricating oil tanks. FIG. 5 is a schematic cross-sectional view of the pump unit corresponding to a cross section taken along line VV of FIG. 2 for explaining the low-pressure diesel suction line. FIG. 3 shows an embodiment of the high-pressure pump of the present invention that is expanded compared to the high-pressure pump of FIG. 2. FIG. 3 shows an improvement of the high-pressure pump according to the invention, reduced compared to the embodiment of FIG. 2. FIG. 2 is a schematic view of a pump unit having a rotating member designed in the form of a slide shoe.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Line module 2 ... Pump unit 4 ... High pressure connection line 5 ... Injection device 6 ... Common rail 7 ... High pressure part 9 ... Drive shaft 10 ... Eccentric drive unit 11 ... Rotating ring 12 ... Sliding bearing 14 ... Plunger 18 ... Supply space 22 ... Housing 24 Low pressure supply line 25 Pressure control inlet valve 26 High pressure output line 27 Pressure control outlet valve 33 Diesel oil tank 36 Cup tappet 37 Plunger hole 47 Slide shoe

Claims (18)

High pressure pump, especially for a co-injection device of an internal combustion engine,
A common drive shaft (9) comprising at least one plunger (14) guided in a hole (37) leading to the supply space (18) and having an eccentric (10) assigned to each said plunger (14). Having a plurality of feed pumps driven by
Each said supply space (18) is connected to a low pressure supply line (24) via a pressure control inlet valve (25) and to a high pressure output line (26) via a pressure control outlet valve (27). ,
The individual feed pumps are designed as modular pumps and can be arranged next to one another via their housings (22) provided with fluid connection passages (24, 26, 31, 34, 41). Yes,
At least one line module (1) connectable to at least one side of the modular unit housing (22);
Said fluid connection passages (24, 26, 31, 34, 41) extend on the one hand further and / or on the other hand to the intake and discharge passages (24 ', 26', 34 ', 41') leading to the outside. A high-pressure pump characterized by being formed. The plunger hole (37) for accommodating the plunger (14) and the supply space (18) are formed in a high-pressure component (7) screwed into the housing (22). Item 2. A high-pressure pump according to item 1. The modular pump units (2) are arranged diametrically opposite one another and are operated by the same eccentric (10), together with the associated supply space (18) and the common housing (22). 3. The high-pressure pump according to claim 1, comprising at least two plungers (14). The plungers (14) are guided in the housing (22) by cup tappets (36) and are pressed against the associated eccentrics (10) by return springs (50). The high-pressure pump according to any one of claims 1 to 3, wherein 5. High pressure according to claim 1, wherein the drive shaft (9) is mounted in at least an outer end wall (13) of the housing (22) at the end of a row of modules. pump. Instead of the drive shaft (9) having both ends attached to the end wall (13) of each housing, the drive shaft (9) is connected at one end with the line module (1) forming one end of the housing. A high-pressure pump according to claim 5, characterized in that a part is mounted and the other end is mounted on the housing end wall (13). 7. The bearing according to claim 1, wherein the bearings for the drive shaft are respectively formed in line modules arranged between adjacent housings. The high-pressure pump according to any one of the above. The high pressure pump according to claim 7, characterized in that the diameter of the bearing (59) is at least slightly larger than twice the maximum radius of the eccentric part (10) of the drive shaft (9). The forced oil supply (30, 31) to the bearing of the drive shaft (9), the rotating ring (11) or the slide shoe (47) and the annular lubricating passage (45) of the cup tappet (36) is provided in the housing. 9. An end piece (15) mounted on an end wall (13) or provided via a line module (1) provided on the end side. High pressure pump as described. Forced oil supply to the bearings is via holes (30, 46) in the drive shaft (9), and forced oil supply to the annular lubrication passage is to the housing (22) and the line module (1). The high-pressure pump according to claim 9, characterized in that it takes place via a passage (31) in the interior. The passages provided in the housing (22) of the pump unit (2) and in the line module (1) are mutually oriented in the axial direction of the high-pressure pump and are sealed at the transition point, so that the low-pressure supply ( 24), high pressure removal of diesel oil, removal of leakage of a mixture of diesel oil and lubricating oil (34), forced oil supply (31), and oil return flow line (41). The high-pressure pump according to any one of claims 1 to 10, wherein It is reciprocated by a common drive shaft (9) provided with an eccentric part (10), guided in plunger holes (37) leading to the supply space (18), respectively, and against the action of the return spring (50). It has a plurality of plungers (14) driven by said eccentrics (10), and an annular collecting space (35) for the overflowing lubricating oil and diesel oil is provided on the supply space side of the wall of the plunger hole (37). The high-pressure pump according to any one of claims 1 to 11, wherein the high-pressure pump is formed at a center position and connected to a diesel oil tank (33) through a passage. It is reciprocated by a common drive shaft (9) provided with an eccentric part (10), guided in plunger holes (37) leading to the supply space (18), respectively, and against the action of the return spring (50). In particular, it has a plurality of plungers (14) driven by said eccentric (10) via cup tappets (36) guided in holes in said housing (22), firstly said drive shaft (9). ) Penetrates and at least one annular lubricating passageway (45) surrounding the respective plunger (14) or cup tappet (36) and formed in said housing (22). Are connected to the lubricating oil pressure supply (30, 31), and an annular space (41 ') connected to the lubricating oil return flow (41) is connected to the plunger (14). High-pressure pump according to any one of claims 1 to 12, characterized in that provided in a portion of the supply space side of the tappet (36). 14. The pressure-maintaining valve (32) is arranged in a passage section (34 ") common to all the passages (34) for leading a mixture of lubricating oil and diesel oil leakage. High pressure pump as described. The high pressure pump according to claim 14, wherein the pressure maintaining valve (32) can be set or controlled. It is reciprocated by a common drive shaft (9) provided with an eccentric part (10), guided in plunger holes (37) leading to the supply space (18), respectively, and against the action of the return spring (50). A plurality of plungers (14) driven by the eccentric portion (10) to which a rotating member is connected, and slide shoes (47, 47 ') having a two-part design are provided as the rotating members. The high-pressure pump according to any one of claims 1 to 15, wherein: Each half of the slide shoes, which can be screwed together, has on the plunger side a bearing plane for each plunger (14) or a cup tappet (36) assigned to the plunger (14). A high-pressure pump according to item 16. High pressure pump according to claim 16 or 17, characterized in that a sliding bearing or a ball bearing is provided between each said eccentric (10) and its associated slide shoe (47, 47 ').

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